We successfully took out that spy satellite:

Late Wednesday night, the U.S.S. Lake Erie used its Aegis missile-defense system to shoot down an ailing reconnaissance satellite as it passed over the Pacific. Aegis is a key piece of the larger U.S. missile-defense system, combining extremely sophisticated ship-borne radars with heat-seeking interceptor missiles that can reach targets in low orbits (such as short- to mid-range ballistic missiles). After successfully using Aegis to knock out a target it was ostensibly never designed for, some may ask if this test of the system proves that the American missile-defense system works.

In a word, the answer is no. The mission is a qualified success for Aegis, since satellites and ballistic missiles share many characteristics at certain stages of flight. But taking out a crippled satellite and destroying an attacking ballistic missile are not the same thing. Most importantly, the satellite’s trajectory was known in great detail and it could not maneuver under its own power. That’s not the case for enemy ballistic missiles, which have unknown trajectories for large portions of their flights (though we can often guess where they’re headed). Advanced missiles, moreover, are likely to be able to maneuver themselves midcourse and release decoys to confuse the missile-defense interceptors. Since shooting a missile out of the sky is a lot like hitting a bullet with another bullet, precise positioning data is crucial.

The question isn’t, “does missile defense work?”  It’s “should we have missile defense?”  And the only reasonable answer is, “no we shouldn’t.” 

The purpose of missile defense is to make the United States safer.  In theory, the ability to shoot down ICBMs should deter any current or potential rivals from doing so.  What isn’t usually said though, is that missile defense would also give the United States first-strike capability.  We would have the option of launching attacks against other nations, without the possibility of suffering meaningful retaliation.

That would be an intolerable situation for every possible adversary and even some allies.  If tomorrow the United States were to unveil a fully functional missile defense system, the very next day, the Chinese and the Russians would announce a massive build up of their nuclear arsenal.  Since the only way they could maintain some degree of deterrence would be to have enough missiles to overwhelm a missile defense system.  We’d be responsible for sparking a second - and probably far more dangerous - nuclear arms race, in addition to souring our relations with two crucial players on the world stage.

I’m inclined to think that anyone pushing for missile defense then (like John McCain) is more interested in having the freedom (for at least a few years) to start new wars, rather than protect the United States (since deterrence has been and is far more effective).

*Before I forget, missile defense is also the most expensive boondoggle ever conceived by the Pentagon.  Missile defense development will cost the country $62.9 billion through 2009.